Introduction to Reverse Osmosis Water Treatment Equipment: Everything You Need to Know!

IV. Reverse Osmosis System Overview

The reverse osmosis system primarily consists of multi-stage high-pressure pumps, reverse osmosis membrane elements, pressure vessels, and support frames. Its main function is to remove impurities from water, ensuring the effluent meets usage requirements. The high-pressure pump elevates the pressure of the water from the safety filter to the operating pressure of the RO system, then evenly distributes it to the pressure vessels. The water flow is separated by the reverse osmosis membranes, forming two streams within the pressure vessels. A portion of the feed water passes through the membranes to become purified water, while the remaining inorganic salts and solid residues are retained and concentrated, forming the concentrate stream, thereby achieving the separation of inorganic salts from water.

Purified water flows out from each pressure vessel containing the reverse osmosis elements, merges, passes through a flow meter, and exits the equipment outlet to enter the pure water tank. The concentrate exits through the concentrate outlet of the pressure vessels.

Reverse Osmosis Membrane Desalination Mechanism: The surface of the semi-permeable membrane is covered with extremely fine pores. The membrane selectively adsorbs a layer of water molecules on its surface, while salt solutes are repelled by the membrane. The higher the valence of the ion, the farther it is repelled. Under the driving force of the reverse osmosis pressure, water molecules around the membrane pores flow out as pure water through capillary action of the membrane, achieving desalination.

When the pore size exceeds that of the reverse osmosis membrane pores, salt solutions can leak through the membrane, with monovalent salts leaking more, divalent salts less, and trivalent salts even less. The pore size of RO membranes is <1.0 nm; therefore, RO membranes can filter out Pseudomonas aeruginosa (3000×10⁻¹⁰ m), one of the smallest bacteria; various viruses such as influenza virus (800×10⁻¹⁰ m) and meningitis virus (200×10⁻¹⁰ m); and even pyrogens (10-500×10⁻¹⁰ m).

Characteristics of producing pure water by reverse osmosis: The equipment is compact, easy to maintain, has a small footprint, and high water production capacity; it produces pure water without phase change, resulting in low energy consumption; furthermore, it does not discharge wastewater containing acids, alkalis, etc., making it a new energy-saving and environmentally friendly device.

The wastewater-to-pure water ratio in reverse osmosis systems is typically 3:1 for small household pure water systems. For small industrial RO systems, a good ratio can reach 1:1, and for large systems, 0.3:0.7. Further reducing wastewater discharge increases costs significantly and will certainly shorten the service life of the RO membranes.

This advanced membrane separation technology is widely used across various fields.

V. Reverse Osmosis System Maintenance

1. Conduct daily water quality testing and record equipment operating parameters; address any abnormalities promptly. Regularly test and record key parameters such as pure water conductivity, pressure at various points, and inlet/outlet flow rates daily.

2. Periodically add regenerant to the brine tank. Set the regeneration time based on actual conditions and water production output. Typically, this is done once every 3-4 days.

3. Replace safety filter cartridges promptly (generally every 3-6 months).

4. Frequently wipe down the machine to keep the equipment clean.

5. Regularly check pipelines for leaks and address them immediately.

6. Ensure normal water and power supply to the equipment. In special circumstances such as power or water outages, readjust the equipment timing, particularly resetting the regeneration time after a power failure. Unauthorized personnel should not touch buttons in the electrical control section or valves in the pipeline section to prevent misuse that could disrupt normal operation.

VI. Emergency Measures

When the equipment loses power or key components such as the main pump or membranes are damaged and cannot produce pure water, the softened water valve can be opened to continue using softened water and ensure the normal operation of water-using equipment. This approach should be based on the actual requirements of the water-using equipment.

1. If the equipment is leaking severely, immediately turn off the water supply switch and power source, then notify the service provider for handling.

2. During water production, if the pressure gauge after the membrane shows exceeds 1.5 MPa, conductivity exceeds 15 μS/cm, or the product water quality exceeds standard ranges, replace consumables such as resin, membranes, and activated carbon promptly.

VII. Consumables Replacement Instructions

Consumables such as quartz sand, activated carbon, and softening resin are granular materials that tend to form a porous structure when accumulated, providing a growth environment for long-term bacterial reproduction. Meanwhile, activated carbon and softening resin have a certain adsorption saturation point; after prolonged use, filtration efficiency decreases. When backwashing and regeneration can no longer meet pretreatment requirements, they should be replaced to ensure the feed water quality for the RO membrane elements.

Under all suitable conditions:

• Quartz sand service cycle: 10-24 months

• Activated carbon service cycle: 10-12 months

• Resin service cycle: 10-12 months

• Precision filter cartridge service cycle: 3-6 months

• Reverse osmosis membrane service cycle: approximately 12 months

Resin regeneration cycle: Under normal conditions, the resin regeneration cycle is 1-3 days.

VIII. Application Fields

1. Power Industry: Boiler feed water, cooling water basins

2. Electronics Industry: Ultrapure water for semiconductor industry, integrated circuit cleaning water, formulation water

3. Food Industry: Formulation water, production water

4. Pharmaceutical Industry: Process water, preparation water, rinsing water, water for injection, sterile water preparation

5. Beverage Industry: Formulation water, production water, rinsing water

6. Chemical Industry: Production water, wastewater treatment

7. Drinking Water Projects: Ultrapure water preparation, drinking water purification

8. Petrochemical Industry: Oilfield injection water, advanced treatment of petrochemical wastewater

9. Seawater Desalination: Production and domestic water for islands, water-scarce coastal areas, ships, offshore oil fields, etc.

10. Environmental Protection: Recovery of precious metals from electroplating rinse water, water recycling, achieving zero liquid discharge.